JPS6079571A - Rotary magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To move a head in a shorter settling time by reproducing a servo signal on a specific track which is determined in the initial time to determine a target value of a servo mechanism for another track and correcting the temperrature in the initial time. CONSTITUTION:Servo correcting data of tracks are stored in an RAM2. The head is moved to the track determined by a CPU at a power-on time. If the innermost circumferential track is the 400th track, the head is moved at intervals of 100 tracks to measure a servo correction quantity of each track. With respect to relations between track positions and servo correction quantities, even if the correction quantity is adjusted to 0 at 25 deg.C on a graph 4, it is necessary that it is corrected to graphs 3 and 5 at 40 deg.C and 15 deg.C. Consequently, temperature correction at this time is possible by correction at intervals of 100 tracks from the determined track at the start time, and the head is moved to a desired track more quickly to shorten the settling time. If the device is started in the state on the graph 4, the shorter settling time is secured because a correction quantity D can be forecast by initial correction when the head is moved from a track T1 to a track T2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary magnetic recording/reproducing device having a servo mechanism.

Conventionally, a rotary magnetic recording/reproducing device having a servo mechanism equipped with a reproducing head, an amplifier circuit, a servo signal detecting circuit, a position error detecting circuit, and a cplL, as shown in FIG.
, a read/write memory (hereinafter referred to simply as RAM), a read-only memory (hereinafter referred to as ROM), a motor drive circuit, and a carriage drive motor.By amplifying the magnetization reversal information read by the playback head with an amplifier circuit, the logic level Or perform electrical processing to the required level. Since servo information is not included in all of the reproduced signals, it is necessary to separate the necessary servo information. This is because there is a fixed detection method determined when servo information is written, and whether the output of the position error detection circuit is valid or invalid is determined by ζC detected by the servo detection circuit. When the position error detection circuit output is valid, the CPG calculates the position error amount and outputs correction corresponding to the result to the motor drive circuit. This corrects the position of the playback head, and this correction remains unchanged until the position error detection signal reaches the target value. The final stable position is most influenced by thermal expansion due to the temperature of the rotary magnetic recording/reproducing device. Therefore, the purpose of the servo mechanism is to correct the track deviation caused by this thermal expansion. When moving the head between tracks, the motor is driven in a certain predetermined state that is independent of temperature, and the servo mechanism is activated from the moment servo information is input. Therefore, in the recessed servo system as shown in Fig. 2, there is an index signal (servo signal (2) immediately before 11) once per revolution.Therefore, servo information is input once per revolution. Several revolutions are required for the head position to reach the target position.In this servo system, where servo information is input quite frequently, the problem is how quickly the head can reach the target position.

The head access time of the rotary magnetic recording/reproducing device is the sum of the head movement time (hereinafter simply referred to as meef time) and the head position stabilization time (hereinafter simply referred to as settling time), so if the settling time is long,
No matter how short the seek time is using a carriage drive motor, the overall time will not be shortened. Therefore, accessing data from the rotary magnetic recording/reproducing device becomes slow, so in a fixed disk, which is an example of a rotary magnetic recording/reproducing device, a servo-only method that does not omit data is called a planar servo method. Some devices have a recording surface to shorten access time.

However, in the surface servo method, one surface of the magnetic recording medium mounted in the rotary magnetic recording/reproducing device cannot be used for data recording/reproducing, so the total amount of information decreases.

The present invention has been made to eliminate such drawbacks.

An embodiment of the present invention will be described with reference to FIGS. 3 and 4.

FIG. 3 has the same configuration as FIG. 1, but RAMI and RAM2, which can be read and written from the CPU, are added. IR
AMI has the same function as R/kM in Figure 1, but
RAM 2 stores servo correction data for each track.

When the power is turned on, the KRB S It T signal is input, and the CP
uK Move to the designated track. If the innermost track is 400 tracks, the outermost track aX
'a towotsuk, ] 00 towotsuku, 200 towotsuku, 30
0) For the book, move the head at intervals of 100 tracks over 400 tracks, and measure the amount of servo correction on each track. FIG. 4 shows the relationship between track position and servo correction amount when a magnetic recording/reproducing medium made of aluminum alloy as a base material is used in an aluminum alloy frame. Even if the adjustment is made with a correction amount of 0 next to graph 4 at 25℃, graph 3 at 40℃
It is necessary to make a positive correction like this. Here, positive correction is correction in the outer circumferential direction. Further, at 15° C., negative correction is performed as shown in graph 5. Therefore, at startup, X'F3. ,) By correcting each 100 tracks from the hook, it is possible to correct the temperature at that time, and it is possible to move the head to the desired track more quickly and shorten the settling time.

When started in the state of graph 4, when moving from track T1 to track T2, the correction amount D can be predicted by the initial correction. If the correction amount changes from C to A when the head is positioned on the track Tl, graph 3 is calculated from the change in the correction amount and the set value of the temperature expansion system. As a result, the correction amount B when moving from track T1 to track T2 can be predicted, and track movement becomes possible with a much faster settling time.

According to such a device, the servo correction amount for each track can be calculated by measuring the correction amount for a specific track in the initial state, and even if the servo correction amount changes due to temperature changes, the servo correction amount can be calculated from the track position. Since the servo correction data on each track can be corrected, the head can be moved with a faster settling time, and the data input/output time in the rotary magnetic recording/reproducing apparatus can be shortened.

In the above explanation, the innermost track is 400 tracks, and the tracks on which the servo correction amount in the initial state is measured are 100 tracks each, but the measurement may be performed using other numbers of tracks or for each track.

As described above, according to the present invention, by measuring the servo correction amount on a specific track in the initial state, the servo correction amount on each track can be calculated, and the head can be moved with a faster settling time. Also, even if the servo correction amount changes due to temperature changes, the servo correction amount for each track can be corrected by calculation based on changes in the track position and servo correction amount, so even if temperature changes occur, the servo correction amount can be corrected quickly. You can move the head between IJ songs. Therefore, in a method such as the recessed servo method in which the servo signal can only be reproduced in a long cycle, a faster settling time can be secured, and even if there is no specific servo surface like in the surface servo, the head movement time can be shortened. become.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining a conventional servo mechanism using the CIJ4 control method. FIG. 2 is a timing diagram for explaining the Umetomi servo system. FIG. 3 is a block diagram 1゜4 for explaining the present invention.
The figure is a graph showing changes in track and servo correction amount due to temperature, for explaining the present invention. (1): Index signal (2): Servo signal 3: Graph 4 at 40°C: Graph 5 at 25°C: Graph A at 15°C: Servo correction amount for track T1 at 40°C. B: Servo correction amount for track T2 at 40°C. C: Servo correction amount for track T1 at 25°C. D=servo correction amount of track T2 applied to 25°C. ,,Jff Figure 1 '52 Figure 3

Claims (1)

[Scope of Claims] 1. A rotary magnetic recording and reproducing device having a servo control circuit composed of a microprocessor C (hereinafter referred to simply as cp) capable of track management and a servo mechanism for correcting the track position. A rotary magnetic recording/reproducing device characterized in that by reproducing a servo signal of a specific track determined at an initial time, target values of servo mechanisms of other tracks are determined and initial temperature correction is performed. 2. The target value of the servo mechanism changes with the passage of time after energization, resulting in a position error due to temperature expansion. This is controlled by a control circuit composed of CPIL.
1. A rotary magnetic recording and reproducing apparatus, comprising: a rotary magnetic recording/reproducing apparatus that corrects target values of servo mechanisms in other tracks based on the sick position and the amount of change in the target value.